The opinion of the court was delivered by: JOSEPH GREENAWAY, District Judge

AMENDED OPINION

This matter comes before the Court on the motion of Barr
Laboratories, Inc. ("Barr"), Impax Laboratories, Inc. ("Impax"),
Teva Pharmaceuticals USA, Inc. ("Teva"), Mylan Pharmaceuticals, Inc. ("Mylan"), Dr. Reddy's Laboratories, Ltd.,
and Dr. Reddy's Laboratories, Inc. ("Reddy"), (collectively
"Defendants"), seeking summary judgment on their claim that U.S.
Patent No. 5,738,872 ("the '872 patent") is invalid as
anticipated, and that the '872 patent, as well as U.S. Patent
Nos. 6,113,942 ("the '942 patent"), 5,855,912 ("the '912
patent"), 5,932,247 ("the '247 patent"), and 6,039,974 ("the '974
patent") are not infringed.*fn1 For the reasons set forth
below, the summary judgment motion of non-infringement of the
'912, '942, and '247 patents is granted. The motion as to the
'974 patent is denied. A ruling on the '872 patent is reserved
pending a Markman hearing to assist this Court in construing
the patent's product-by-process claims. The scope of the
Markman hearing shall be set forth below.

BACKGROUND

This dispute concerns patents owned by Aventis Pharmaceuticals,
Inc., Merrell Pharmaceuticals Inc., and Carderm Capital L.P.
(collectively "Plaintiffs" or "Aventis") disclosing solid dosage
fexofenadine formulations sold in the United States by Aventis
under the tradenames ALLEGRA® and ALLEGRA-D® These antihistamine
allergy medication products have achieved substantial commercial
success in the United States. Between May 2001 and November 2002,
Defendants each filed Abbreviated New Drug Applications ("ANDA")
seeking the Federal Drug Administration's ("FDA") approval to
market generic drug products containing the same active
ingredients (fexofenadine hydrochloride ("fexofenadine") and
pseudoephedrine hydrochloride) as Aventis' ALLEGRA® and ALLEGRA-D®
products.*fn2 In connection with their ANDA submissions,
Defendants filed so-called "Paragraph IV Certifications"
asserting that the Aventis patents*fn3 were invalid,
unenforceable, or would not be infringed by the commercial
manufacture, use, or sale of their drug products.*fn4 In
response to notice of Defendants' Paragraph IV Certifications,
and acting pursuant to statutorily prescribed
procedures,*fn5 Plaintiffs commenced these, now consolidated, patent infringement actions.

Defendants have filed the instant motions for summary judgment
arguing that their accused products do not literally infringe the
'942, '912, '274, and '974 patents, and further, that there can
be no finding of infringement under the doctrine of equivalents.
Defendants contend that Plaintiffs are barred from asserting the
doctrine of equivalents by prosecution history estoppel, and in
the alternative, are precluded from relying on the doctrine of
equivalents because Plaintiffs' patents have dedicated inert
ingredients or excipients used by Defendants in their accused
products to the public. With respect to the '872 patent,
Defendants argue that their accused products do not infringe, and
that the '872 patent is invalid, as anticipated by the prior art.

This Court will address infringement issues initially with
respect to the '942, '912, '274, and '974 patents, followed by a
focus on the inquiry into the validity of the '872 patent.

If the nonmoving party has failed "to make a showing sufficient
to establish the existence of an element essential to that
party's case, and on which that party will bear the burden of
proof at trial, . . . there can be `no genuine issue of material
fact,' since a complete failure of proof concerning an essential
element of the nonmoving party's case necessarily renders all
other facts immaterial." Katz v. Aetna Cas. & Sur. Co.,
972 F.2d 53, 55 (3d Cir. 1992) (quoting Celotex,
477 U.S. at 322-23). In determining whether there are any issues of material
fact, the Court must resolve all doubts as to the existence of a
material fact against the moving party and draw all reasonable
inferences  including on issues of credibility  in favor of the
non-moving party. Watts v. Univ. of Del., 622 F.2d 47, 50 (3d
Cir. 1980).

II. Infringement

The test for patent infringement requires a two step analysis:
"First, the claim must be properly construed to determine its scope and meaning. Second,
the claim as properly construed must be compared to the accused
device or process." Carroll Touch, Inc. v. Electro Mech. Sys.,
Inc., 15 F.3d 1573, 1576 (Fed. Cir. 1993). "In order for a court
to find infringement, the plaintiff must show the presence of
every limitation or its substantial equivalent in the accused
device." KX Industries v. PUR Water Purification Products, 2001
WL 902507 *3 (Fed. Cir. 2001) (citing Wolverine World Wide, Inc.
v. Nike, Inc., 38 F.3d 1192, 1199 (Fed. Cir. 1994)). Although
claim construction is an issue of law, the determination of
infringement is a question of fact. Id.

A product may infringe a patent either literally or
equivalently. Cybor Corp. v. FAS Techs., 138 F.3d 1448, 1459
(Fed. Cir. 1998). Plaintiffs cannot argue that each limitation of
the claims at issue in patents '942, '912, '274, and '974, are
satisfied exactly by the accused products, as required to prove
literal infringement. Instead, they rely on the doctrine of
equivalents which "prevents an accused infringer from avoiding
liability for infringement by changing only minor or
insubstantial details of a claimed invention while retaining the
invention's essential identity." Festo Corp. v. Shoketsu Kinzoku
Kogyo Kabushiki Co., 234 F. 3d 558, 564 (Fed. Cir. 2000)
("Festo VI"). Infringement under the doctrine of equivalents is
found "only when a patentee shows by a preponderance of the
evidence that the accused product or process contain[s] elements identical or equivalent to each
claimed element of the patented invention." Warner-Jenkinson Co.
v. Hilton Davies Chem. Co., 520 U.S. 17, 40 (1997).

Application of the doctrine of equivalents requires a fact
intensive analysis to determine whether or not differences
between a claim limitation of the patent, and the corresponding
element of the accused device, are merely insubstantial or
unimportant substitutions. In certain cases, however, the law
restricts application of the doctrine of equivalents without
further fact finding. This occurs when a patentee is found to
have dedicated equivalent subject matter to the public, or where
prosecution history estoppel bars application of the doctrine of
equivalents.

The '912, '942, '974, and '247 patents generally claim
fexofenadine formulations with certain combinations of
excipients, including pregelatinized starch, croscarmellose
sodium, and microcrystalline cellulose. These excipients are not
present in Defendants' accused product formulations.*fn6 For
the purposes of this motion, it is assumed that defendants Barr,
Impax, Teva, and Mylan's accused tablets substitute povidone, and
Reddy substitutes mannitol as an equivalent for pregelatinized
starch as a binder; Barr and Mylan substitute crospovidone, and
Impax substitutes sodium starch glycolate for croscarmellose
sodium as a disintegrant; and Barr and Reddy substitute powdered
cellulose for microcrystalline cellulose as a diluent.

PROSECUTION HISTORY ESTOPPEL

I. Standard for the Bar of Prosecution History Estoppel to
Availability of the Doctrine of Equivalents in an Infringement
Action

Prosecution history estoppel may bar a patentee from asserting
infringement under the doctrine of equivalents:

[T]here are limits to the application of the doctrine
of equivalents aside from the question of
insubstantiality of the differences . . .
[P]rosecution history estoppel can prevent a patentee
from relying on the doctrine of equivalents when the
patentee relinquishes subject matter during the
prosecution of the patent, either by amendment or
argument.

Eagle Comtronics, Inc. v. Arrow Commun. Labs., Inc.,
305 F.3d 1303, 1315 (Fed. Cir. 2002). There are thus two different kinds
of prosecution history estoppel: that based on amendment, and
that based on argument.

A. Amendment-Based Estoppel

The Supreme Court established the standard for amendment-based
estoppel in Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki
Co., 535 U.S. 722 (2002) ("Festo VIII"). The basic principle
is: "[a] narrowing amendment made to satisfy any requirement of
the Patent Act may give rise to an estoppel." Id. at 736. A
patentee making such an amendment is presumed to have surrendered
the territory for purposes of the doctrine of equivalents, and
bears the burden of rebutting this presumption.

[W]e hold here that the patentee should bear the
burden of showing that the amendment does not
surrender the particular equivalent in question. The
patentee, as the author of the claim language, may be
expected to draft claims encompassing readily known
equivalents. A patentee's decision to narrow his
claims through amendment may be presumed to be a
general disclaimer of the territory between the
original claim and the amended claim.

Id. at 740. The Court held that there are three ways in which a
patentee may rebut this presumption:

The equivalent may have been unforeseeable at the
time of the application; the rationale underlying the
amendment may bear no more than a tangential relation
to the equivalent in question; or there may be some
other reason suggesting that the patentee could not
reasonably be expected to have described the
insubstantial substitute in question.

Id. Even if estoppel applies, however, the patentee may
demonstrate that the narrowing amendment did not surrender the particular equivalents at issue.
Id. at 741. "The standard for determining whether particular
subject matter was relinquished is an objective one that depends
on what a competitor reasonably would conclude from the patent's
prosecution history." Mark 1 Marketing, Corp. v. R.R. Donnelley
& Sons Co., 66 F.3d 285, 291 (Fed. Cir. 1995).

The issue of whether prosecution history estoppel bars the
availability of the doctrine of equivalents in an infringement
action is a matter of law. "We have stated on numerous occasions
that whether prosecution history estoppel applies, and hence
whether the doctrine of equivalents may be available for a
particular claim limitation, presents a question of law." Festo
Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 344 F.3d 1359,
1367 (Fed. Cir. 2003) ("Festo IX"). Any resolution of factual
issues underlying these questions of law may be decided by the
court, not the jury. Id. at 1369.

B. Argument-Based Estoppel

The Federal Circuit has extended the principles of prosecution
history estoppel to arguments made by an applicant during patent
prosecution, producing a second category of estoppel:
argument-based estoppel. "Clear assertions made during
prosecution in support of patentability, whether or not actually
required to secure allowance of the claim, may also create an
estoppel." Southwall Techs., Inc. v. Cardinal IG Co.,
54 F.3d 1570, 1583 (Fed. Cir. 1995). "To invoke argument-based estoppel,
the prosecution history must evince a clear and unmistakable
surrender of subject matter." Eagle Comtronics,
305 F.3d at 1316. Thus, the legal standards for amendment-based estoppel and
argument-based estoppel differ greatly.

II. Prosecution History Estoppel Does Not Bar Availability of
the Doctrine of Equivalents in Plaintiffs' Action for
Infringement of the '974 Patent

The '974 patent is for a two-layer tablet, with one layer of
antihistamine (from the genus of which fexofenadine is one
species) and another layer of decongestant. Defendants make only one argument relating to the examiner's statements in the office
action allowing the claims: "[h]aving failed to contest the
P.T.O.'s stated reasons for allowance, Plaintiffs have disallowed
any broader constructions." (Impax Br. at 20). That single
sentence contains Defendants' entire argument on this
matter.*fn7 Defendants propose no legal theory to explain
why Plaintiffs have disallowed any broader constructions. They
cite no case law, and their reply brief does not even discuss the
'974 patent. Non-response to a statement in an office action does
not qualify for consideration as either amendment-based estoppel
or argument-based estoppel. Defendants have failed to show a
basis for their claim.

III. Prosecution History Estoppel Bars Availability of the
Doctrine of Equivalents in Plaintiffs' Actions for Infringement
of the '942 and '912 Patents

Both Plaintiffs and Defendants agree that the written
descriptions of the '942 and '912 patents are virtually
identical, and do not differ materially for the purposes of this
summary judgment motion. Plaintiffs and Defendants have argued
the two patents together, and they are considered together in
this opinion.

A. Prosecution History of the '942 and '912 Patents

The '942 and '912 patents descended from three related
applications: 1) application 08/395,952 was filed on February 28,
1995, and abandoned, but continued in part by 2) application
08/552,287, filed on December 12, 1995, and abandoned, but
continued in part by 3) application 08/943,460 for the present
patents, filed October 3, 1997. The '912 patent was granted
directly from the last-mentioned application, and the '942 patent
is a divisional offspring of that application. The claims in the first application, 08/395,952, are all
pharmaceutical composition claims for a combination of an active
ingredient and one or more inert ingredients. The record shows
that the P.T.O. response to the first application, the first
office action, was directed to the generic nature of the claims,
finding that they encompassed a plurality of species, and seeking
restriction or election of species. (Gresalfi Decl. at A270-272.)
Applicants responded by electing the species of
fexofenadine, with a group of specific inert ingredients
(croscarmellose sodium, microcrystalline cellulose, lactose,
pregelatinized starch, gelatin and magnesium stearate), for a
group of the claims. (Gresalfi Decl. at A274.) The P.T.O. then
responded by reiterating the restriction requirement for the
claims that did not involve the elected formulation, and it
rejected the claims involving the elected formulation as
anticipated and/or obvious. (Gresalfi Decl. at A278-281).

The applicants then filed the second application, 08/552,287,
as a continuation-in-part of the first. The claims in the second
application were of two types: most were pharmaceutical
composition claims which varied from very broad and generic
formulations to very specific formulations, while some were
product-by-process claims. The P.T.O. responded by again seeking
restriction/election for some claims and rejecting others under
35 U.S.C. §§ 102(b) and 103 (Gresalfi Decl. at A385-A390). The
examiner's comments in this first office action are nearly
identical to the comments in the first office action for the
first application. Applicants then cancelled all claims except
for the product-by-process claims, and added new composition
claims for fexofenadine formulations with specific inert
ingredients (croscarmellose sodium, microcrystalline cellulose,
lactose, pregelatinized starch, and gelatin; some formulations
also included magnesium stearate). (Gresalfi Decl. at A392-A394.) At this point, a significant change occurred in the
specification of inert ingredients. As originally filed, claims
in the second application referred specifically to the inert
ingredients croscarmellose sodium, lactose, microcrystalline
cellulose, pregelatinized starch, gelatin, calcium carbonate,
magnesium stearate, and sodium starch glycolate. (Gresalfi Decl.
at A355-A366.) The applicant cancelled all claims which specified
the inert ingredients calcium carbonate and sodium starch
glycolate, and added claims not specifying those two inert
ingredients. Those two inert ingredients did not appear in the
third application (08/943,460), nor are they specified in the
claims in either the '942 or '912 patents. This is a crucial
point in the prosecution history for this dispute, and the
discussion below will focus on those events.

The P.T.O. next reexamined this group of old and new claims and
rejected all of them as obvious over prior art, focusing on the
particular inert ingredients croscarmellose sodium,
microcrystalline cellulose, lactose, pregelatinized starch, and
gelatin. (Gresalfi Decl. at A404.) Applicants filed a reply to
this rejection, arguing, in brief, that the combinations of
fexofenadine with the particular inert ingredients were not
obvious from the prior art. (Gresalfi Decl. at A407-410.) The
P.T.O. responded by reversing its rejection and allowing the
previously rejected claims. Nonetheless, the applicants abandoned
the application.

The applicants then filed the third application as a
continuation of the second, adding some new claims, but
essentially restricting the patent to the specific formulations
claimed in the amended second application. These claims were
allowed. The '912 patent was granted directly from the third
application, and the '942 patent is a divisional offspring of
that application. B. Narrowing Amendments Were Made for Reasons of Patentability
of the '942 and '912 Patents

The parties do not dispute that the applicant made narrowing
amendments during the prosecution history of the '942 and '912
patents. The applicant had previously eliminated most claims with
generic formulations when, in response to the first office action
to the second application, the applicant cancelled the claims
with the remaining generic references to inert ingredients. From
this point on, the application contained only claims with
combinations of specific inert ingredients. At this point, then,
the claim amendments narrowed their scope.

The focus of the parties' dispute here is the actual reason for
the narrowing amendments. Plaintiffs argue that the applicants
made narrowing amendments not for reasons of patentability, but
to comply with the examiner's election/restriction requirements.
Defendants argue that the narrowing amendments were made for
reasons of patentability.

Plaintiffs argue that they cancelled the claims in response to
the election/restriction requirements, not in response to the
rejections for patentability. This argument must fail for several
reasons, but the simplest is that it does not match the facts. In
the first office action to the second application, the examiner
rejected claims 1-10, 14-17, 22-24, 29, and 31-35 under
35 U.S.C. §§ 102(b) and 103; the examiner determined that claims
11-13, 18-21, 25-28, 30, and 36-43 were subject to
restriction/election requirements. (Gresalfi Decl. at A385.)
Claims 1 and 3 were the broadest claims. The examiner rejected
Claims 1 and 3 and the applicant then cancelled the claims.
Plaintiffs cannot maintain that they cancelled these broad claims
in response to a restriction requirement. The prosecution history
clearly shows that they were cancelled due to a rejection, and thus necessarily for reasons of
patentability. This analysis alone defeats Plaintiffs' argument.

In addition, the Federal Circuit has held that a series of
narrowing applications may form the basis for a finding of
surrender of claim coverage. In Mark I Mktg. Corp. v. R.R.
Donnelley & Sons Co., 66 F.3d 285, 292 (Fed. Cir. 1995), cert.
denied, 516 U.S. 1115 (1996), the patentee "chose to file
continuing applications with successively narrower claims in lieu
of otherwise responding to the P.T.O.'s rejections," and the
Court held that the patentee had surrendered claim coverage. To
argue here that the patentees filed a series of narrowing claims,
in the context of repeated rejections for reasons of
patentability, but that the narrowing claims were not filed for
reasons of patentability, is far-fetched.

Moreover, even if one were to assume, arguendo, that the
changes were made only because of the restriction/election
requirements, Plaintiffs assert incorrectly that such an action
would preclude the application of prosecution history estoppel.
Plaintiffs argue, in effect, for a per se rule that restriction
requirements and requests for election of species cannot invoke
prosecution history estoppel. Yet the Federal Circuit has not
established a per se rule; rather, it has held that whether
restriction requirements invoke prosecution ...

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